1. Field of the Invention
The present invention relates to a multiple control system for a composite electronic apparatus in which a plurality of electronic devices are incorporated, and more particularly to a multiple control system for driving individually a display element used commonly by the plurality of electronic devices.
2. Description of the Related Art
In general, a display unit is provided in a composite electronic apparatus in which a plurality of electronic devices are incorporated for common use by the respective electronic devices. The display unit is connected to one of the plurality of electronic devices, so that the electronic device so connected to the display unit allows display data such as operating conditions of the other electronic devices to be displayed on the display unit. FIG. 4 shows a conventional example. In FIG. 4, a microcomputer 11 is directly connected to a driver IC 13, whereby the microcomputer 11 sends a display data signal to the driver IC 13 so as to control the driver IC 13 to control, in turn, a display element 14, so that display data can be displayed on the display unit 14. Since a microcomputer 12 is not directly connected to the driver IC 13, the microcomputer 12 sends a display data signal to the microcomputer 11, and the microcomputer 11 then receives the display data signal. Then, the microcomputer 11 sends the display data signal to the driver IC 13, so that the display data can be displayed on the display unit 14. The conventional example shown in FIG. 4 will be described in greater detail.
Namely, what is shown in FIG. 4 is a block diagram of a main part of a so-called dual deck (a composite video recording and reproducing apparatus) having both a reproducing capability from a DVD (Digital Versatile Disc) and a recording and reproducing capability on and from a VHS tape. A schematic perspective view of an external appearance of the dual deck is shown in FIG. 5.
In FIG. 5, reference numeral 15 denotes a reproducing functional part capable of reproducing from a DVD, reference numeral 16 a recording and reproducing functional part capable of recording and reproducing on and from a VHS tape, and reference numeral 14 a common display panel (a display element) for displaying various conditions (a reproducing position, fast feeding and rewinding) of the DVD reproducing functional part 15 and the VHS recording and reproducing functional part 16.
Then, the microcomputer 12 shown in FIG. 4 is a microcomputer for united control of the DVD reproducing functional part 15 and the microcomputer 11 is a microcomputer for united control of the VHS recording and reproducing functional part 16.
In a case where a reproducing from a certain DVD is being executed in the DVD reproducing functional part 15, a reproducing position on the disc is displayed on the display panel 14 in such a form of “1:10:30” (1 hour, 10 minutes, 30 seconds), and in a case where a certain VHS tape is being fed fast in the VHS recording and reproducing functional part 16, a display such as “FF” (fast forward) is displayed on the display panel 14.
As an apparatus configured such that a plurality of microcomputers send a display data signal directly to a driver IC for driving a display element, there has been proposed an apparatus as disclosed in, for example, JP-A-6-274134 which is configured such that a clock signal for a liquid crystal display and a synchronous signal for frame synchronization are sent from a microcomputer to another microcomputer and clock signals and synchronous signals outputted from the two microcomputers are synchronized with each other, so that the two microcomputers each installing therein a driver IC perform their own shared responsibilities to simultaneously drive the liquid crystal display element having a number of pixels.
Of the aforesaid examples described with respect to the related art, however, in the former example (shown in FIGS. 4 and 5), while the display data such as the operating conditions of the respective microcomputers can be displayed on the display element via the single microcomputer, a data signal line and a control signal line for sending the display data signal and the control signal from the microcomputer 12 to the microcomputer 11, respectively, are needed. In particular, in the event that the display data signal and the control signal are sent via a serial communication with a small number of data signal lines and control signal lines, there is caused a problem that a communication control is required for sending and receiving signals such as the display data signal.
The problem with the former example will be described in greater detail.
Namely, while the driver IC 13 outputs a drive signal for driving the display element 14 towards individual grids or segments of the display element that are to be illuminated, the contents of the output thereof are outputted from the microcomputer 11 towards the driver IC 13 as serial data. The serial data outputted towards the driver IC 13 are created within the microcomputer 11.
For example, in the event that the “FF” is attempted to be displayed on the display element 14 with the VHS recording and reproducing functional part 16 performing a fast feeding operation of the VHS tape, the microcomputer 11 converts the display “FF” which indicates the current operating condition (fast feeding condition) of the VHS recording and reproducing functional part 16 which is recognized by the microcomputer itself into data (data of the grids or segments) that can be received by the driver IC 13 and outputs the data so converted to the driver IC 13. Since the microcomputer 11 is originally such as to govern the united control of the VHS recording and reproducing functional part 16, although the microcomputer 11 allows the various conditions of the VHS recording and reproducing functional part 16 to easily be displayed on the display element as has been described above, it is not easy to enable the display of the conditions of the DVD reproducing functional part 15 via the microcomputer 11.
Assuming that, for example, the DVD reproducing functional part 15 is implementing a reproducing from a position of 1 hour, 10 minutes and 30 seconds on a disc, in the event that the microcomputer 12 wants to display “1:10:30” on the display element 14 via the microcomputer 11, the following will happen.
That is, while the microcomputer 12 outputs data to the microcomputer 11 to cause the microcomputer 11 to output the data towards the driver IC 13 so as to enable the display of “1:10:30” on the display element 14, in order for the microcomputer 11 to recognize correctly the data outputted from the microcomputer 12 to the microcomputer 11, in addition to the function to display the operating conditions of the VHS recording and reproducing functional unit 16, a function to display the operating conditions of the DVD reproducing functional part 15 needs to be provided within the microcomputer 11. In the case of the system shown in FIG. 4, the microcomputer 11 needs the function to recognize data relating to the conditions of the DVD reproducing functional part 15 which are inputted from the microcomputer 12 in addition to the function to output the conditions of the VHS recording and reproducing functional part 16 as the display data to be displayed on the display element.
In addition, even if the function as has just been described above is installed in the microcomputer 11, since the microcomputer 12 cannot output the data relating to the display of the conditions towards the microcomputer 11 while, for example, the microcomputer 11 is controlling the VHS recording and reproducing functional unit 16, information on the conditions of the microcomputer 11 needs to be inputted into the microcomputer 12 at all times (the microcomputer 12 side needs to recognize the conditions of the microcomputer 11 side at all times), a complicated control is needed for exchanging data between the microcomputer 11 and the microcomputer 12 (for example, a BUSY signal in FIG. 4).
Then, since the microcomputer 11 for controlling the VHS recording and reproducing functional part 16 is normally connected to another microcomputer (for example, a microcomputer for a TUNER), a control is needed for exchanging data between the microcomputer 11 and the another microcomputer. Thus, the control becomes further complicated.
In any case, in the system as shown in FIG. 4 in which a microcomputer for outputting the display data to the driver IC 13 is fixed to the single particular microcomputer 11, there is caused a drawback that the input and output of data into and from the microcomputer 11 becomes complicated.
In addition, in the latter example (disclosed in JP-A-6-274134), while the single display element can be driven via the driver ICs connected to the two microcomputers, respectively, there exists a problem that the data signal line and the control signal line are needed for sending and receiving display data signals and control signals between the two microcomputers. Additionally, while the two microcomputers are configured to directly drive the display element, the pixels of the display element are driven by the two microcomputers in a shared fashion, and the apparatus is not such that the display data such as the operating conditions of the two microcomputers are displayed on the display element by the two microcomputers, respectively.